Method of propulsion for vessels and screw-propeller for effecting the same.



J. HAHN.

METHOD OF PROPULSION FOR VESSELS AND SCREW PROPELLER FOR EFFECTING THE SAME.

APPLICATION FILED JULY 16, 1914 T. T 9Ufi55. Patented July 11, 1916.

JOHN HAHN, F LOS ANGELES, CALIFORNIA.

METHOD OF PROPULSION FOR VESSELS AND SCREW-PROPELLER FOR EFFEGTING THE SAME.

propeller will be maximized, and the provi- S1011 of a propeller having a higher degree of efficiency than propellers of corresponding dimensions of the type -heretofore known.

The invention relates in some respects to that type of screw-propelller provided with fluid discharge vents in its blades, which ports were designed in some instances to discharge air at the front side of the propeller to eliminate the back suction due to the partial vacuum said to be created by the rapidly revolving propellerand which ports in other instances were designed to discharge water at the rear side of the propeller to relieve the partial vacuum caused by movement of the vessel through the water so as to overcome the so-called slip.

More specifically the invention comprises a. propeller having a vane or vanes and means to discharge air or other gases at the rear faces of the vanes along the median lines of the vanes so as to produce for each vane a wedge of resisting fluid to relieve the partial vacuum that would result if said fluid were not supplied, and to prevent the fluid medium in which the propeller is immersed from being thrust with too great ease by the vanes from the fore half of the vanes due to the usual tendency of said medium to slip from the fore half of the vanes into the partial vacuum space created adjacent the rear half of the vanes under working conditions when fluid is not supplied to relieve the partial vacuum.

Another object of the invention is to accomplish the foregoing results by a simple and practical construction.

With propellers of the kind heretofore constructed, the medium in which the propeller turns tends to be given a centrifugal movement outward from the axis of the pro- Specification of Letters Patent.

v Fig. 9.

Patented July fl, 1916.

Application filed July 16, 1914.. Serial No. 851,417.

peller, and another object is to minimize such centrifugal movement and thus overcome or materially reduce this component of the so termed slip of the propeller. The construction relied upon to overcome the sllp due to said centrifugal movement is transverse vanes extending crosswise of the blades, in one instance from the longitudinal axes of the blades to the discharge edges of the blades, and in another instance from the recelving edges to the discharge edges of the blades so that air or gases issuing from along the median lines of the vanes will strike said transverse vanes and aid in turn ing the propeller and also react to aid in thrusting the propeller forward.

Further objects and advantages may ap pear as the invention is unfolded more in detail. in the drawings filed herewith and in the subjoined description.

The accompanying drawings illustrate the invention.

Figure 1 is a side elevation of one form of the invention partly in section on irregu lar line indicated by w w Figs. 3 and 4. Fig. 2 is an end elevation from the left of Fig. 1 and from the arrow 2, Figs. 3 and 4, the shaft and a portion of one of the blades being in section. Fig. 3 is a plan section from line indicated by W, Figs. 1 and. 2', omitting the shaft. Fig. 4; is an inverted plan section from line indicated by 00*, Figs. 1 and 2, omitting the shaft. Fig. 5 is an inverted plan section fi om line indicated by as, Figs. 1 and 2 omitting the shaft. Fig. (3 is a view of a difierent form of shaft than the shaft in Fig. 1. Fig. 7 is a rear view of a difl'erent form of my improved propeller from the form shown in Figs. 1 to 5. Fig. 8 is a cross section of one of the blades on irregular line indicated by m w Fig. 7. Fig. 9 is a fragmental rear elevation of still another form of my improved propeller.

Fig. 10 is a plan section of one of the blades on irregular line indicated by sa -a3 Viewed from the front and rear, the blades 1, 2 of the propeller may be of the usual or any preferred contour and are preferably quite broad at their outer ends similar to the blades of high speed propellers.

The drawings show two-blade propellers, but it is understood that a difi'erent number 6 with the bore 7 of a hollow tubular shaft form the front walls of distributing chambers 4 extending lengthwise from the inner to the outer ends of the blades and extending crosswise from near the receiving fore edges 5 to substantially the,long1tud1nal axes of the blades; and said chambers communicate at their inner ends through ports SasinFigzLl The chambers 4 are provided at said longitudinal axes of the blades with vents 9 of any desired number and size, and preferably as shown in the drawings these vents are one continuous vent for each chamber and each vent is practically as long and wide as the chamber is long and wide fore and aft.

The chambers 4C are quite thin, and consequently the vents 9 are narrow so that fluid passing through the vents will be directed by each vent in a single continuous thin film; and the axes of the vents are substantially parallel to the vanes 3 so that the fluid ,films will be directed along the rear their longitudinal faces of the vanes from mid axes toward the discharge aft edges 10 of the blades.

The foregoing details apply to all'of the forms illustrated in the drawings and the diflerentiating features will now be described.

Inthe form shown in Figs. 7 and 8 the blades 1, 2 are each provided with a transverse secondary vane 11 extending crosswise of the vane 3 from the rear edge of the chamber 4 to the discharge edge 10; and in the form shown in Figs. 9 and 10 the blade is provided with a transverse secondary vane 12 extending crosswise of the vane 3 from the receiving edge 5 to the discharge edge 10.

- mixture of gases constituting the atmosphere but to include other gases such as the exhaust gases of gas engines.

In practice power will be applied to turn the propeller shaft 8 in the usual manner ward through the to move the blades 1, 2 in the direction of the large feathered arrows in Figs. 2, 7 and 9 and compressed air or gases under pressure such as the exhaust gases of gas engines will be supplied to the tubular shaft 8 from a suitable source, not shown. The air or gases will pass from the tubular shaft through the ports 6 into the distributing chambers l and from thence said air or gases will be discharged through the vents 9 in a thin sheet or film overcoming the tendency to the formation of a partial vacuum at the rear of the propeller, which partial vacuum, were it to exist, would produce back suction and consequent loss of power. f

Another great advantage of my construction now appears and is derived whatever the nature of the fluid inwhich the propeller turns, for in respect to the currents produced in them by moving elements water and air function alike. Referring now more particularly to Fig. 3 it is seen that the vane 3 as it revolves will cleave with its receiving edge 5 the fluid in which it is placed and those fluid particles adjacent the rear face of the vane will circle rearward in eddies indicated by small curved arrows a. Owing to the creation of eddies corresponding to the eddies a propellers heretofore constructed have an effective thrust face extending only from the receiving edge to approximately the longi'- tudinal mid axis of the blade. It is noted thatthe vents 9 are located substantially along said longitudinal mid axis of the blade so that the effective thrust face not only extends from the receiving edge 5 to said mid axis but also extends from said mid axis to the discharge edge 10, the air or gases issuing from said vents circliy rearward in eddies indicated by small curi ei l thus about twice as great as with propellers of prior construction. It is also noted that by reason of the vents 9 discharging parallel to the blades, the reac'- tion of the discharge upon the blades occurs at the angle best suited to aid in turning the blades and to thrust the propeller forresisting fluid. If it be desired to discharge air or gases from the blades alone the constructor will use the form of shaft shown in Figs. 6 and 7, but if it be desired to discharge vair or gases directly from thepropeller shaft into the water or air, then the constructor will use the form of shaft shown in Fig. 1, and

peller shown in Figs. 7 to 10 air or gases will discharge from the vents 9 between the macaw shaft 8 and the transverse vanes 11 or 12 as the case may be, said air or gases and also the water between the shaft and transverse vanes will be held against centrifugal movement so that the thrust of the propeller will be maximized and slip will be minimized.

It is noted that by locatingthe vents 9 along the median lines of the vanes the effective thrust of the fore half of the vanes is not diminished but rather is.,increased by reason of the vented air or gases filling in the partial vacuum space and preventing relative slip between the fore half of the vanes and the medium in which the propeller is working; and that the effective thrust of the rear half of the vanes is greatly increased by reason of the partial vacuum being eliminated so that said rear half will thrust against a resisting medium the same as does the fore half. Furthermore it is noted that the air or gases issuing from the vents will strike the transverse vanes 11 or 12, as the case may be, and aid in turning the propeller and also by reaction thrust, the propeller forward.

When the exhaust gases from a. gas engine are exhausted through the vents 9, it

is readily understood that besides obtaining the advantages noted above the power, of the gas engine is increased because of the tendency of the propeller to create a partial vacuum adjacent the vents, thus producing suction on the exhaust gases from the engine.

I claim 1. The method of propulsion for ves sels, which method comprises discharging fluid under pressure along the median line of the. vanes of a propeller so that said fluidwill resist the thrust of the rear half of the vanes and will prevent the medium in which the propeller is working from slipping rearward along the fore half of'said vanes.

2. The method (if propulsion for vessels, which method comprises exhausting the .burned gases from an internal combustion engine under their discharge pressure along the median line of the vanes of a propeller at the rear faces of the vanes so that said gases will resist the thrust of the rear half lli'ill of the vanes'and will prevent the medium in which the propeller is working from slipping along the fore half of the said vanes and so as to maximize the power of said engine.

3. In combination a hollow shaft, propeller blades mounted on the shaft and having distributing chambers extending lengthwise from the inner to the outer ends of the blades and extending'crosswise from near the receiving fore edges to substantially the longitudinal axes of the blades and having ports opening from the chambers to the bore of the shaft, said chambers being provided at said longitudinal axes with vents opening on the rear faces of the blades so that gases will pass from said chambers to the space at the rear of the rear half of the blades to prevent creation of a partial vacuum adjacent said rear half.

4. The method of propulsion for vessels, which method comprises discharging fluid under pressure along only the median line of the vanes of a propeller at the rear faces of the vanes so that said fluid will resist the V thrust of the rear half of the vanes and will prevent the medium in which the propeller is working from slipping rearward along the fore half of said vanes.

5. A screw propeller having vents along only the median line of its blades at the rear faces of said blades.

6. A screw propeller having vents along only the median line of its blades at the rear faces of the blades, alnd transverse vanes on the blades to receive the thrust of fluidissuing from said vents.

7. A screw propeller having chambered blades with vents to the chambers along only the longitudinal mid axes of the blades at the rear faces of the blades, said vents being directed toward the rear edges of the blades, and means to supply fluid to the chambers. I

In testimony whereof, I have hereunto set my hand. at Los Angeles, California this 11th day of July, 1914.

JOHN HAHN.

In presence of- GEORGE I-I. I-IrLns, EMMA ll-Irnns. 

